mirror of
https://github.com/rocky-linux/peridot.git
synced 2024-12-25 20:00:27 +00:00
522 lines
14 KiB
Go
522 lines
14 KiB
Go
package xpath
|
|
|
|
import (
|
|
"errors"
|
|
"fmt"
|
|
)
|
|
|
|
type flag int
|
|
|
|
const (
|
|
noneFlag flag = iota
|
|
filterFlag
|
|
)
|
|
|
|
// builder provides building an XPath expressions.
|
|
type builder struct {
|
|
depth int
|
|
flag flag
|
|
firstInput query
|
|
}
|
|
|
|
// axisPredicate creates a predicate to predicating for this axis node.
|
|
func axisPredicate(root *axisNode) func(NodeNavigator) bool {
|
|
// get current axix node type.
|
|
typ := ElementNode
|
|
switch root.AxeType {
|
|
case "attribute":
|
|
typ = AttributeNode
|
|
case "self", "parent":
|
|
typ = allNode
|
|
default:
|
|
switch root.Prop {
|
|
case "comment":
|
|
typ = CommentNode
|
|
case "text":
|
|
typ = TextNode
|
|
// case "processing-instruction":
|
|
// typ = ProcessingInstructionNode
|
|
case "node":
|
|
typ = allNode
|
|
}
|
|
}
|
|
nametest := root.LocalName != "" || root.Prefix != ""
|
|
predicate := func(n NodeNavigator) bool {
|
|
if typ == n.NodeType() || typ == allNode || typ == TextNode {
|
|
if nametest {
|
|
if root.LocalName == n.LocalName() && root.Prefix == n.Prefix() {
|
|
return true
|
|
}
|
|
} else {
|
|
return true
|
|
}
|
|
}
|
|
return false
|
|
}
|
|
|
|
return predicate
|
|
}
|
|
|
|
// processAxisNode processes a query for the XPath axis node.
|
|
func (b *builder) processAxisNode(root *axisNode) (query, error) {
|
|
var (
|
|
err error
|
|
qyInput query
|
|
qyOutput query
|
|
predicate = axisPredicate(root)
|
|
)
|
|
|
|
if root.Input == nil {
|
|
qyInput = &contextQuery{}
|
|
} else {
|
|
if root.AxeType == "child" && (root.Input.Type() == nodeAxis) {
|
|
if input := root.Input.(*axisNode); input.AxeType == "descendant-or-self" {
|
|
var qyGrandInput query
|
|
if input.Input != nil {
|
|
qyGrandInput, _ = b.processNode(input.Input)
|
|
} else {
|
|
qyGrandInput = &contextQuery{}
|
|
}
|
|
// fix #20: https://github.com/antchfx/htmlquery/issues/20
|
|
filter := func(n NodeNavigator) bool {
|
|
v := predicate(n)
|
|
switch root.Prop {
|
|
case "text":
|
|
v = v && n.NodeType() == TextNode
|
|
case "comment":
|
|
v = v && n.NodeType() == CommentNode
|
|
}
|
|
return v
|
|
}
|
|
qyOutput = &descendantQuery{Input: qyGrandInput, Predicate: filter, Self: true}
|
|
return qyOutput, nil
|
|
}
|
|
}
|
|
qyInput, err = b.processNode(root.Input)
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
}
|
|
|
|
switch root.AxeType {
|
|
case "ancestor":
|
|
qyOutput = &ancestorQuery{Input: qyInput, Predicate: predicate}
|
|
case "ancestor-or-self":
|
|
qyOutput = &ancestorQuery{Input: qyInput, Predicate: predicate, Self: true}
|
|
case "attribute":
|
|
qyOutput = &attributeQuery{Input: qyInput, Predicate: predicate}
|
|
case "child":
|
|
filter := func(n NodeNavigator) bool {
|
|
v := predicate(n)
|
|
switch root.Prop {
|
|
case "text":
|
|
v = v && n.NodeType() == TextNode
|
|
case "node":
|
|
v = v && (n.NodeType() == ElementNode || n.NodeType() == TextNode)
|
|
case "comment":
|
|
v = v && n.NodeType() == CommentNode
|
|
}
|
|
return v
|
|
}
|
|
qyOutput = &childQuery{Input: qyInput, Predicate: filter}
|
|
case "descendant":
|
|
qyOutput = &descendantQuery{Input: qyInput, Predicate: predicate}
|
|
case "descendant-or-self":
|
|
qyOutput = &descendantQuery{Input: qyInput, Predicate: predicate, Self: true}
|
|
case "following":
|
|
qyOutput = &followingQuery{Input: qyInput, Predicate: predicate}
|
|
case "following-sibling":
|
|
qyOutput = &followingQuery{Input: qyInput, Predicate: predicate, Sibling: true}
|
|
case "parent":
|
|
qyOutput = &parentQuery{Input: qyInput, Predicate: predicate}
|
|
case "preceding":
|
|
qyOutput = &precedingQuery{Input: qyInput, Predicate: predicate}
|
|
case "preceding-sibling":
|
|
qyOutput = &precedingQuery{Input: qyInput, Predicate: predicate, Sibling: true}
|
|
case "self":
|
|
qyOutput = &selfQuery{Input: qyInput, Predicate: predicate}
|
|
case "namespace":
|
|
// haha,what will you do someting??
|
|
default:
|
|
err = fmt.Errorf("unknown axe type: %s", root.AxeType)
|
|
return nil, err
|
|
}
|
|
return qyOutput, nil
|
|
}
|
|
|
|
// processFilterNode builds query for the XPath filter predicate.
|
|
func (b *builder) processFilterNode(root *filterNode) (query, error) {
|
|
b.flag |= filterFlag
|
|
|
|
qyInput, err := b.processNode(root.Input)
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
qyCond, err := b.processNode(root.Condition)
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
qyOutput := &filterQuery{Input: qyInput, Predicate: qyCond}
|
|
return qyOutput, nil
|
|
}
|
|
|
|
// processFunctionNode processes query for the XPath function node.
|
|
func (b *builder) processFunctionNode(root *functionNode) (query, error) {
|
|
var qyOutput query
|
|
switch root.FuncName {
|
|
case "starts-with":
|
|
arg1, err := b.processNode(root.Args[0])
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
arg2, err := b.processNode(root.Args[1])
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
qyOutput = &functionQuery{Input: b.firstInput, Func: startwithFunc(arg1, arg2)}
|
|
case "ends-with":
|
|
arg1, err := b.processNode(root.Args[0])
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
arg2, err := b.processNode(root.Args[1])
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
qyOutput = &functionQuery{Input: b.firstInput, Func: endwithFunc(arg1, arg2)}
|
|
case "contains":
|
|
arg1, err := b.processNode(root.Args[0])
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
arg2, err := b.processNode(root.Args[1])
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
|
|
qyOutput = &functionQuery{Input: b.firstInput, Func: containsFunc(arg1, arg2)}
|
|
case "substring":
|
|
//substring( string , start [, length] )
|
|
if len(root.Args) < 2 {
|
|
return nil, errors.New("xpath: substring function must have at least two parameter")
|
|
}
|
|
var (
|
|
arg1, arg2, arg3 query
|
|
err error
|
|
)
|
|
if arg1, err = b.processNode(root.Args[0]); err != nil {
|
|
return nil, err
|
|
}
|
|
if arg2, err = b.processNode(root.Args[1]); err != nil {
|
|
return nil, err
|
|
}
|
|
if len(root.Args) == 3 {
|
|
if arg3, err = b.processNode(root.Args[2]); err != nil {
|
|
return nil, err
|
|
}
|
|
}
|
|
qyOutput = &functionQuery{Input: b.firstInput, Func: substringFunc(arg1, arg2, arg3)}
|
|
case "substring-before", "substring-after":
|
|
//substring-xxxx( haystack, needle )
|
|
if len(root.Args) != 2 {
|
|
return nil, errors.New("xpath: substring-before function must have two parameters")
|
|
}
|
|
var (
|
|
arg1, arg2 query
|
|
err error
|
|
)
|
|
if arg1, err = b.processNode(root.Args[0]); err != nil {
|
|
return nil, err
|
|
}
|
|
if arg2, err = b.processNode(root.Args[1]); err != nil {
|
|
return nil, err
|
|
}
|
|
qyOutput = &functionQuery{
|
|
Input: b.firstInput,
|
|
Func: substringIndFunc(arg1, arg2, root.FuncName == "substring-after"),
|
|
}
|
|
case "string-length":
|
|
// string-length( [string] )
|
|
if len(root.Args) < 1 {
|
|
return nil, errors.New("xpath: string-length function must have at least one parameter")
|
|
}
|
|
arg1, err := b.processNode(root.Args[0])
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
qyOutput = &functionQuery{Input: b.firstInput, Func: stringLengthFunc(arg1)}
|
|
case "normalize-space":
|
|
if len(root.Args) == 0 {
|
|
return nil, errors.New("xpath: normalize-space function must have at least one parameter")
|
|
}
|
|
argQuery, err := b.processNode(root.Args[0])
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
qyOutput = &functionQuery{Input: argQuery, Func: normalizespaceFunc}
|
|
case "replace":
|
|
//replace( string , string, string )
|
|
if len(root.Args) != 3 {
|
|
return nil, errors.New("xpath: replace function must have three parameters")
|
|
}
|
|
var (
|
|
arg1, arg2, arg3 query
|
|
err error
|
|
)
|
|
if arg1, err = b.processNode(root.Args[0]); err != nil {
|
|
return nil, err
|
|
}
|
|
if arg2, err = b.processNode(root.Args[1]); err != nil {
|
|
return nil, err
|
|
}
|
|
if arg3, err = b.processNode(root.Args[2]); err != nil {
|
|
return nil, err
|
|
}
|
|
qyOutput = &functionQuery{Input: b.firstInput, Func: replaceFunc(arg1, arg2, arg3)}
|
|
case "translate":
|
|
//translate( string , string, string )
|
|
if len(root.Args) != 3 {
|
|
return nil, errors.New("xpath: translate function must have three parameters")
|
|
}
|
|
var (
|
|
arg1, arg2, arg3 query
|
|
err error
|
|
)
|
|
if arg1, err = b.processNode(root.Args[0]); err != nil {
|
|
return nil, err
|
|
}
|
|
if arg2, err = b.processNode(root.Args[1]); err != nil {
|
|
return nil, err
|
|
}
|
|
if arg3, err = b.processNode(root.Args[2]); err != nil {
|
|
return nil, err
|
|
}
|
|
qyOutput = &functionQuery{Input: b.firstInput, Func: translateFunc(arg1, arg2, arg3)}
|
|
case "not":
|
|
if len(root.Args) == 0 {
|
|
return nil, errors.New("xpath: not function must have at least one parameter")
|
|
}
|
|
argQuery, err := b.processNode(root.Args[0])
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
qyOutput = &functionQuery{Input: argQuery, Func: notFunc}
|
|
case "name", "local-name", "namespace-uri":
|
|
if len(root.Args) > 1 {
|
|
return nil, fmt.Errorf("xpath: %s function must have at most one parameter", root.FuncName)
|
|
}
|
|
var (
|
|
arg query
|
|
err error
|
|
)
|
|
if len(root.Args) == 1 {
|
|
arg, err = b.processNode(root.Args[0])
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
}
|
|
switch root.FuncName {
|
|
case "name":
|
|
qyOutput = &functionQuery{Input: b.firstInput, Func: nameFunc(arg)}
|
|
case "local-name":
|
|
qyOutput = &functionQuery{Input: b.firstInput, Func: localNameFunc(arg)}
|
|
case "namespace-uri":
|
|
qyOutput = &functionQuery{Input: b.firstInput, Func: namespaceFunc(arg)}
|
|
}
|
|
case "true", "false":
|
|
val := root.FuncName == "true"
|
|
qyOutput = &functionQuery{
|
|
Input: b.firstInput,
|
|
Func: func(_ query, _ iterator) interface{} {
|
|
return val
|
|
},
|
|
}
|
|
case "last":
|
|
qyOutput = &functionQuery{Input: b.firstInput, Func: lastFunc}
|
|
case "position":
|
|
qyOutput = &functionQuery{Input: b.firstInput, Func: positionFunc}
|
|
case "boolean", "number", "string":
|
|
inp := b.firstInput
|
|
if len(root.Args) > 1 {
|
|
return nil, fmt.Errorf("xpath: %s function must have at most one parameter", root.FuncName)
|
|
}
|
|
if len(root.Args) == 1 {
|
|
argQuery, err := b.processNode(root.Args[0])
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
inp = argQuery
|
|
}
|
|
f := &functionQuery{Input: inp}
|
|
switch root.FuncName {
|
|
case "boolean":
|
|
f.Func = booleanFunc
|
|
case "string":
|
|
f.Func = stringFunc
|
|
case "number":
|
|
f.Func = numberFunc
|
|
}
|
|
qyOutput = f
|
|
case "count":
|
|
//if b.firstInput == nil {
|
|
// return nil, errors.New("xpath: expression must evaluate to node-set")
|
|
//}
|
|
if len(root.Args) == 0 {
|
|
return nil, fmt.Errorf("xpath: count(node-sets) function must with have parameters node-sets")
|
|
}
|
|
argQuery, err := b.processNode(root.Args[0])
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
qyOutput = &functionQuery{Input: argQuery, Func: countFunc}
|
|
case "sum":
|
|
if len(root.Args) == 0 {
|
|
return nil, fmt.Errorf("xpath: sum(node-sets) function must with have parameters node-sets")
|
|
}
|
|
argQuery, err := b.processNode(root.Args[0])
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
qyOutput = &functionQuery{Input: argQuery, Func: sumFunc}
|
|
case "ceiling", "floor", "round":
|
|
if len(root.Args) == 0 {
|
|
return nil, fmt.Errorf("xpath: ceiling(node-sets) function must with have parameters node-sets")
|
|
}
|
|
argQuery, err := b.processNode(root.Args[0])
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
f := &functionQuery{Input: argQuery}
|
|
switch root.FuncName {
|
|
case "ceiling":
|
|
f.Func = ceilingFunc
|
|
case "floor":
|
|
f.Func = floorFunc
|
|
case "round":
|
|
f.Func = roundFunc
|
|
}
|
|
qyOutput = f
|
|
case "concat":
|
|
if len(root.Args) < 2 {
|
|
return nil, fmt.Errorf("xpath: concat() must have at least two arguments")
|
|
}
|
|
var args []query
|
|
for _, v := range root.Args {
|
|
q, err := b.processNode(v)
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
args = append(args, q)
|
|
}
|
|
qyOutput = &functionQuery{Input: b.firstInput, Func: concatFunc(args...)}
|
|
case "reverse":
|
|
if len(root.Args) == 0 {
|
|
return nil, fmt.Errorf("xpath: reverse(node-sets) function must with have parameters node-sets")
|
|
}
|
|
argQuery, err := b.processNode(root.Args[0])
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
qyOutput = &transformFunctionQuery{Input: argQuery, Func: reverseFunc}
|
|
default:
|
|
return nil, fmt.Errorf("not yet support this function %s()", root.FuncName)
|
|
}
|
|
return qyOutput, nil
|
|
}
|
|
|
|
func (b *builder) processOperatorNode(root *operatorNode) (query, error) {
|
|
left, err := b.processNode(root.Left)
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
right, err := b.processNode(root.Right)
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
var qyOutput query
|
|
switch root.Op {
|
|
case "+", "-", "div", "mod": // Numeric operator
|
|
var exprFunc func(interface{}, interface{}) interface{}
|
|
switch root.Op {
|
|
case "+":
|
|
exprFunc = plusFunc
|
|
case "-":
|
|
exprFunc = minusFunc
|
|
case "div":
|
|
exprFunc = divFunc
|
|
case "mod":
|
|
exprFunc = modFunc
|
|
}
|
|
qyOutput = &numericQuery{Left: left, Right: right, Do: exprFunc}
|
|
case "=", ">", ">=", "<", "<=", "!=":
|
|
var exprFunc func(iterator, interface{}, interface{}) interface{}
|
|
switch root.Op {
|
|
case "=":
|
|
exprFunc = eqFunc
|
|
case ">":
|
|
exprFunc = gtFunc
|
|
case ">=":
|
|
exprFunc = geFunc
|
|
case "<":
|
|
exprFunc = ltFunc
|
|
case "<=":
|
|
exprFunc = leFunc
|
|
case "!=":
|
|
exprFunc = neFunc
|
|
}
|
|
qyOutput = &logicalQuery{Left: left, Right: right, Do: exprFunc}
|
|
case "or", "and":
|
|
isOr := false
|
|
if root.Op == "or" {
|
|
isOr = true
|
|
}
|
|
qyOutput = &booleanQuery{Left: left, Right: right, IsOr: isOr}
|
|
case "|":
|
|
qyOutput = &unionQuery{Left: left, Right: right}
|
|
}
|
|
return qyOutput, nil
|
|
}
|
|
|
|
func (b *builder) processNode(root node) (q query, err error) {
|
|
if b.depth = b.depth + 1; b.depth > 1024 {
|
|
err = errors.New("the xpath expressions is too complex")
|
|
return
|
|
}
|
|
|
|
switch root.Type() {
|
|
case nodeConstantOperand:
|
|
n := root.(*operandNode)
|
|
q = &constantQuery{Val: n.Val}
|
|
case nodeRoot:
|
|
q = &contextQuery{Root: true}
|
|
case nodeAxis:
|
|
q, err = b.processAxisNode(root.(*axisNode))
|
|
b.firstInput = q
|
|
case nodeFilter:
|
|
q, err = b.processFilterNode(root.(*filterNode))
|
|
case nodeFunction:
|
|
q, err = b.processFunctionNode(root.(*functionNode))
|
|
case nodeOperator:
|
|
q, err = b.processOperatorNode(root.(*operatorNode))
|
|
}
|
|
return
|
|
}
|
|
|
|
// build builds a specified XPath expressions expr.
|
|
func build(expr string) (q query, err error) {
|
|
defer func() {
|
|
if e := recover(); e != nil {
|
|
switch x := e.(type) {
|
|
case string:
|
|
err = errors.New(x)
|
|
case error:
|
|
err = x
|
|
default:
|
|
err = errors.New("unknown panic")
|
|
}
|
|
}
|
|
}()
|
|
root := parse(expr)
|
|
b := &builder{}
|
|
return b.processNode(root)
|
|
}
|